Penny+Lab+Pictures

The transformation of metals into useful resources has created our modern industrial age. In this lab students mixed two different metals, zinc and copper, to produce an alloy called brass. This is a technique commonly used to manufacture costume jewelry. Brass exists in two different forms depending on the ratio of zinc to copper.

The silver colored brass (B) is formed when there is a high concentration of zinc. After the silver penny is heated, a gold surface appears which is called alpha brass. This happens when the concentration of zinc drops below 35% of the mixture. This procedure is a physical change and does not create changes in the elctron structure of the metallic atoms. back